net fetcher: re-use headers on redirect
net fetcher: re-use headers on redirect

if we arbitrarily set the cookie header, we have the potential
to set it to nil, which will raise an exception initializing
the HTTP request

rapid7/omnibus,intfrr/omnibus,Altiscale/omnibus,ashhher3/omnibus,rhass/omnibus,3ofcoins/chef-omnibus,pskrz/omnibus,DataDog/omnibus-ruby,mattray/omnibus,adamleff/omnibus,sh9189/omnibus,Scalr/omnibus,hugosato/omnibus,higanworks/omnibus,strangelittlemonkey/omnibus,servebox/omnibus,ashhher3/omnibus,chef/omnibus,mattray/omnibus,chef/omnibus,3ofcoins/chef-omnibus,lvfeng1130/omnibus,strangelittlemonkey/omnibus,servebox/omnibus,higanworks/omnibus,lvfeng1130/omnibus,pskrz/omnibus,intfrr/omnibus,adamleff/omnibus,jamesn/omnibus,rhass/omnibus,DataDog/omnibus-ruby,intfrr/omnibus,rapid7/omnibus,jamesn/omnibus,adamleff/omnibus,szechyjs/omnibus,ashhher3/omnibus,strangelittlemonkey/omnibus,mattray/omnibus,jamesn/omnibus,sh9189/omnibus,rhass/omnibus,Altiscale/omnibus,chef/omnibus,hugosato/omnibus,Scalr/omnibus,servebox/omnibus,3ofcoins/chef-omnibus,pskrz/omnibus,szechyjs/omnibus,lvfeng1130/omnibus,DataDog/omnibus-ruby,hugosato/omnibus,Scalr/omnibus,szechyjs/omnibus,rapid7/omnibus,Altiscale/omnibus,sh9189/omnibus,higanworks/omnibus